How to avoid the volunteer trap

Volunteers sort donated food at the Capital Area Food Bank in Washington, D.C.

FORTUNE — For many volunteers, the old adage about no good deed going unpunished rings all too true. My own experiences include time wasted as a volunteer youth mentor, attempted animal rescuer, and pro bono attorney, to name just a few.

For those looking to give back to their communities, whether for altruistic or professional reasons, finding the right fit can mean the difference between advancing worthy causes — including your career — or simply having a new place to play CandyCrush.

According to the U.S. Bureau of Labor Statistics, in 2012, about 64.5 million people volunteered through or for an organization in the U.S. There are plenty of reasons to volunteer. To start, there is the basic, reciprocal obligation to participate in the community where you live. “I look at each individual as a communitarian — they are linked to the community where they live, so there is a responsibility to give back,” says Robert Earl, director of Barnard College’s Career Development Office and the Reverend at Harlem’s Mount Calvary Baptist Church.

Volunteering is not simply an altruistic decision. Many of us want to get something out of it, too. “Volunteering is also a wonderful opportunity to develop skills that are transferable within the work world, meet diverse people, and gain leadership skills,” Earl says.

But that doesn’t mean every volunteer role will provide those benefits. If you don’t do your homework beforehand, you will pay a price down the line.

First and foremost, make sure you’re pursuing a cause you’re passionate about, whatever that cause may be. For Catie Marron, co-chair of the board of directors of Friends of the High Line and a trustee and former chairman of the board of The New York Public Library, that was public spaces, particularly parks and libraries. Her recently published book, City Parks: Public Spaces, Private Thoughts, is the culmination of passions she pursued as a volunteer, albeit a high ranking one. While she can list the benefits parks and libraries provide — “from literacy training to computer training to giving people a safe spot to go at the end of the day when there’s nowhere else that’s open” — her involvement stemmed from her own interests. “I just happen to love nature in the city,” she says, noting that everyone is different. “If you love music or art, that’s where you should get involved. All of these things do good for the world. They’re all altruistic.”

This may seem like common sense, but as Lynda Zugec, the managing director of The Workforce Consultants, observes, “Oftentimes, people just think, ‘Oh, this is available,’” and take whatever is offered. (Writer’s note: Guilty as charged.)

Instead of jumping at the first opportunity that comes your way, do some research about what is needed in the areas that interest you. Volunteermatch.org matches cause-driven volunteers with organizations that need them. Volunteers of America lets would-be do-gooders search positions by interest, and some municipalities provide similar services. (New Yorkers, for example, can check out NYCService.org, which allows users to search by priority as well as passion.)

Once you’ve narrowed down your interests, vetted the organization, and set up an interview, don’t stop asking questions. “The most important thing for an individual to do when he or she is looking for a volunteer opportunity is to understand where they want to get to,” Zugec says. “The key in finding something that’s going to be worthwhile and help you down the road is to know your end goal,” whether that’s learning new technical skills, working on your bedside manner, or feeding the hungry.

Don’t be shy about making sure your goals are realistic. Not everyone can join the Peace Corps or rescue refugees from war-torn countries. For Marron, it was important to find a way to contribute that allowed her to spend time with her family. “There are harder ways to volunteer than I’ve done, and tougher ways where you can certainly make more of a difference, but I’ve chosen a way that seems to suit me,” she says, noting that her particular financial circumstances allow her to participate in a way not everyone has the freedom to do. “To use what I’ve been given to try to help people really means a lot to me. And I am very lucky that I don’t have to make a salary, so I’ve had the benefit of being able to go this route.”

After you’ve figured out what you want to achieve, don’t keep the information to yourself. “You want to be able to sit down with the organization’s contact person and have a conversation about exactly what you’re going to be doing,” Earl advises. Set up a meeting with the coordinator to discuss your objectives and the outcomes you want.

Beware the organization that doesn’t give you the chance to have that meeting. “Make sure that it’s a two-way conversation, that you’re able to convey and articulate what your learning outcomes will be from this opportunity. If you can’t do that, it’s an immediate red flag,” Earl warns, noting that poorly organized institutions offer less worthwhile volunteer opportunities.

If the interviewer can’t answer questions about your responsibilities or your day-to-day schedule, they may have just put out a call for a volunteer without knowing how that person will help, and you may be able to adjust the situation to your advantage. For some people, that can offer a chance to do great things – but that kind of uncertainty is not for everyone.

Even once you have taken all of these precautions, though, you may still find yourself unsatisfied. In that case, Earl recommends bowing out gracefully, something that is easier to do if you’ve already expressed the goals you want to meet. “Now you can say, ‘Per our conversation, I thought I would be doing x, y, and z,’” he says. If the position can’t be changed to meet those goals, “Wish them well in their mission and what they’re doing in the community, and then go back to the websites and start over.”